The invention relates to the manufacture of briquettes from wet mineral ore, including coal particles.
It is known that dry pulverized ore can be pelletized with the aid of a bitumen emulsion. This is a useful method for the recovery of mineral ore dust which otherwise would be difficult to handle. However, this method has the disadvantage that the pellets produced have a low density and a low crushing strength, and therefore it is often difficult to subject the resultant pellets to further treatment. The obvious way to obtain agglomerates having a higher density and a better crushing strength would be to process the ore into briquettes instead of pellets.
This method, however, has two drawbacks. In the first place, the briquetting is not possible with ore that is present in the form of a wet cake originating, for example, from flotation processes or other separation processes in a wet medium, (for example, gravity separation of coal from stones in water) or with muds originating from scrubbing the fumes from steel converters. When treating these wet cakes or muds with an aqueous bitumen emulsion, agglomeration is difficult with muds and cakes having a high water content. In the second place, when using briquetting presses having tangential rolls for compressing the continuous feed of agglomerates into briquettes, the latter will not leave the machine owing to clogging of the cells of the rolls.